Immune complex nephropathy in mixed connective tissue disease.

Initial reports on the clinical spectrum of mixed connective tissue disease (MCTD) indicated that renal involvement was uncommon. Four of 20 patients with MCTD underwent renal biopsy and all showed evidence of immune complex trapping with a membranous glomerulonephritis in three patients. Clinically evident renal disease was absent in two patients. These findings suggest that renal involvement in MCTD may be more prevalent than previously indicated.